经电流重构后，请问PWM写入数据函数怎么理解？

//! brief     Writes PWM data to the PWM comparators for motor control//! param[in] handle    The hardware abstraction layer (HAL) handle//! param[in] pPwmData  The pointer to the PWM datastatic inline void HAL_writePwmData(HAL_Handle handle,HAL_PwmData_t *pPwmData)[  uint_least8_t cnt;  HAL_Obj *obj = (HAL_Obj *)handle;  PWM_Obj *pwm;  _iq period;  _iq pwmData_neg;  _iq pwmData_sat;  _iq pwmData_sat_dc;  _iq value;  uint16_t value_sat;  for(cnt=0;cnt<3;cnt++)    [      pwm = (PWM_Obj *)obj->pwmHandle[cnt];      period = (_iq)pwm->TBPRD;      pwmData_neg = _IQmpy(pPwmData->Tabc.value[cnt],_IQ(-1.0));      pwmData_sat = _IQsat(pwmData_neg,_IQ(1.0),_IQ(-1.0));      pwmData_sat_dc = _IQmpy(pwmData_sat + _IQ(1.0), _IQ(0.5));      value = _IQmpy(pwmData_sat_dc, period);      value_sat = (uint16_t)_IQsat(value, period, _IQ(0.0));      // write the PWM data      PWM_write_CmpA(obj->pwmHandle[cnt],value_sat);    ]  return;]在这个函数中，for循环部分，特别是下面这段：
period = (_iq)pwm->TBPRD;      pwmData_neg = _IQmpy(pPwmData->Tabc.value[cnt],_IQ(-1.0));      pwmData_sat = _IQsat(pwmData_neg,_IQ(1.0),_IQ(-1.0));      pwmData_sat_dc = _IQmpy(pwmData_sat + _IQ(1.0), _IQ(0.5));      value = _IQmpy(pwmData_sat_dc, period);      value_sat = (uint16_t)_IQsat(value, period, _IQ(0.0));这段怎么理解？求各位大神指教啊！！